Rambus Inc. patents, it's a two-fer

United States Patent 7,184,483
Rajan February 27, 2007

Technique for emulating differential signaling

Abstract
A technique for emulating differential signaling is disclosed. In one exemplary embodiment, the technique is realized by encoding a plurality of input signals so as to generate a plurality of encoded signals having a spatial run length of N, wherein N is an integer having a value of at least two. Each of the plurality of encoded signals is then transmitted over a transmission medium so as to provide a respective plurality of transmitted encoded signals. Each of the plurality of transmitted encoded signals is then compared with at least N neighboring others of the plurality of transmitted encoded signals so as to recover a representation of each of the plurality of encoded signals. Each of the plurality of recovered encoded signals is then decoded so as to generate a plurality of decoded signals representing the plurality of input signals.
Inventors: Rajan; Suresh (San Jose, CA)
Assignee: Rambus Inc. (Los Altos, CA)
Appl. No.: 11/326,343
Filed: January 6, 2006

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United States Patent 7,183,805
Wang , et al. February 27, 2007

Method and apparatus for multi-mode driver
Abstract
Multi-mode signal drivers with a single output circuit that may be controlled using a mode select input and that may include a common mode (CM) voltage compensation mechanism are described. In a first exemplary implementation, a multi-mode output driver is adapted to drive signals from a single output circuit according to at least two modes, such as a current mode logic (CML) signaling mode and a low voltage differential signaling (LVDS) mode. In a second exemplary implementation, a circuit comprises a quasi-LVDS output driver in which a differential amplifier circuit is connected in series with an adjustable resistive element and a programmable current source. In a third exemplary implementation, a CM voltage of an output driver circuit changes with changes to a programmable bias current. To compensate, a feedback mechanism provides a compensation signal to a variable resistive element of the output driver circuit to maintain a desired CM voltage.
Inventors: Wang; Yueyong (Sunnyvale, CA), Daly; Barry W. (Sunnyvale, CA), Nguyen; Nhat M. (San Jose, CA), Frans; Yohan U. (Palo Alto, CA)
Assignee: Rambus Inc. (Los Altos, CA)
Appl. No.: 11/385,234
Filed: March 20, 2006

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